When an IV access device is identified as being “closed” or “integrated,” it generally refers to the fact that the device is configured to prevent blood from escaping the device during insertion of the catheter. Typically, such IV access devices accomplish this by integrating an extension set with the catheter adapter.
FIG. 1 illustrates an example of a prior art closed IV access device 100. Device 100 includes a catheter adapter 101 from which a catheter 101a extends, a needle hub 102 from which a needle 102a extends, an extension tube 103 that is coupled to catheter adapter 101 at one end and includes a Y-adapter 104 coupled to the other end, and a clamp 107 for blocking or limiting fluid flow through extension tube 103. Y-adapter 104 includes a port 105 and a vent plug 106. Device 100 can be a closed system by incorporating fluid flow blocking components (e.g., a septum or vent) into each external opening of the device such as into a proximal end of catheter adapter 101 and into any ports in adapter 104.
To facilitate proper insertion of the needle in a closed system, it is typical for the needle to include a flashback notch towards its distal end. This flashback notch is oftentimes positioned within the catheter so that blood flowing out through the flashback notch will be visible within the catheter. When blood is seen flowing through the flashback notch, the clinician can know that the needle tip is contained within a vein. However, a flashback notch alone may not be sufficient to provide confirmation of proper catheter placement. For example, even if the needle tip is contained within the vein, the tip of the catheter may not be. Also, during needle withdrawal, it is possible that the catheter tip may be displaced from within the vein.
For these reasons, closed IV access devices oftentimes are configured to allow blood to flow into the extension tube to provide a secondary confirmation of proper catheter placement. For example, access device 100 may include a vent plug that is coupled to a port of luer adapter 104. The vent plug can allow air to escape from extension tube 103 thereby allowing the patient's blood pressure to cause blood to flow into extension tube 103. If blood flows into extension tube 103, the clinician can know that the tip of catheter 101a is properly positioned within the patient's vein.
Although using the extension tube of a closed system is an effective way of providing secondary confirmation of proper catheter placement, some catheter insertion techniques prevent it from being used. For example, it is common in some countries to prime extension tube 103 with saline solution prior to inserting catheter 101a. In such cases, because extension tube 103 will be filled with saline during catheter insertion, blood will not flow into extension tube 103 to provide the secondary confirmation.